Increased Risk of Bilateral Infection

Hypothesis: Simultaneous bilateral endoprosthetic total hip or knee arthroplasty (as in the current article) is in theory inevitably associated with an increased rate of bilateral infections.

Reasoning: A department specific risk of infection due to surgery—for example, 5/1000—for endoprosthetic total hip or knee arthroplasty means that even for simultaneous bilateral surgery, such a risk of infection exists (if not even a higher risk, which we will not consider here). If one furthermore assumes that in case of surgery both surgical sites may be affected—the current article does not provide any information in this respect—then the risk of bilateral infection may be 5/1000 if all cases of infection are always bilateral or, for example, 5/10 000 if only one in 10 cases of infection is bilateral.

In two-stage surgery (with an interval of several weeks between procedures) the risk per intervention is 5/1000. Both interventions combined have a risk of infection of 2×5/1000=10/1000 for an infection to affect one joint.

The probability that in a two-stage procedure (with an interval of several weeks between procedures) both joints become infected is 5/1000×5/1000=25/1000 000.

In order to be able better to balance these very divergent surgical risks it would be necessary to obtain detailed data on the bilateral proportion of infections in the group of patients having had simultaneous surgery.

Unrelated to that, statistical probability in simultaneous bilateral surgery works against the surgeon, which is why I personally do not recommend this procedure to my patients.

DOI: 10.3238/arztebl.2012.0114a

Dr. med. Wolfgang Herzberg

Unfallchirurgie und Orthopädie

ASKLEPIOS Westklinikum Hamburg

herzberg@gmx.de

Conflict of interest statement

The author declares that no conflict of interest exists.